Cable grounding, three position, snap action switch



Aug'- 2 1965 I A. J. CHARBONNEAU 3,264,420

CABLE GROUNDING, THREE POSITION, -SNAP ACTION SWITCH Filed July l, 19642 Sheets-Shed' l /n @2275/2 b/ {gag/072726021, f Wm "M55/ Aug- 2 1966 A.J. CHARBONNEAU CABLE-GROUNDING. THREE POSITION, SNAP ACTION SWITCH 2Sheets-Sheet 2 Filed July l, 1964 z@- if j( 142 f O ,/00 54 M- 5@ O :il

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United States Patent O "ice 3,264,420 CABLE GROUNDING, THREE POSITION,SNAP ACTIGN SWITCH Albert J. Charbonneau, Pittsfield, Mass., assignor toGeneral Electric Company, a corporation of New York Filed July 1, 1964,Ser. No. 379,550 3 Claims. (Cl. 20G-48) This invention relates to threeposition switches and more lparticularly to switches that are providedwith a three position, snap action, havin-g a cable grounding positionwhich find special utility in distribution loop feed systems.

In recent years, distribution systems for distributing electrical powerto consumers have changed i-n many respects. Among these changes hasbeen the increased usage of a type of distribution system which has beentermed the open loop feed system. In this system, a plurality ofdistribution transformers are connected in an open loop to a source ofelectrical power. In such open loop cfeed systems each distributiontransformer is provided with connecting means for two energized powerlines. Either or both of these power lines may be connected to theVarious distribution transformers of the open loop feed system'. Whenone distribution transformer or a cable section between distributiontransformer's develops a fault requiring its removal, the remainingdistribution transformers in the loop system can still be energized bythe alternate cables. As will be understood, the loop is always open atone lpoint or section andthe distribution transformers on each side ofthe open section are connected to 1an energized line from the source ofelectrical power.

One problem which has arisen in the use of open loop ifeed systems isthe need of a mean-s for removing a transformer from the line, whendesired, or a means for sectionalizing a portion of the loop feedsystem. Sectionalizing, las used herein, means to isolate a portion Vofthe loop feed system which connects two or more adjacent transformers inthe system. For example, when it is necessary to remove a transformerfrom the line for inspection or repair, or a change-out, it is desiredthat the energized lines to the transformer be de-e-nergized before workisv begun on that transformer. Further, when it is desired to inspectthe wire or cable or to replace the wire or cable which connect twodistribution transformers of Ithe system it is, of course, desirablethat this portion of the line be de-energized; that is, that theparticular section of power cable between .two transformers besectionalized by removing it from the source of power. To perfor-m theabove functions either the transformer must be disconnected from the twoenergized lines or the line which is connected tothe two transformersmust be disconnected from each of the transformers. As will be apparentto those skilled in the art, it is preferred that this disconnection beaccomplished by switching means in each transformer.

It has recently been proposed to provide a single three I positionswitch for each transformer of -a loop feed system. This three positionswitch generally provides a switch which either connects .thetransformer to both energized lines or which may be -operated to connectthe transformer to either energized line. Such a three position switchis described and claimed in application serial No. 168,479, tiled Ian.24, 1962, for Three Position Snap Action Switch, in the name of GeraldP. Hermann, now Patent No. 3,150,213, issued Sept, 22, 1964, whichapplication -is assigned to the same assignee as this application. Whilethe three position switch disclosed and claimed in the Hermannapplication nds great utility in 4loop feed systems, it is consideredunacceptable by some electric utilities. These electric utilities, whichconsider 3,264,420 Patented August 2, 1966 the Hermann switchunacceptable, require that provisions be made for grounding the cablewhich is de-energized, such as is necessary in sectionalizing a portionof the power cable between two transformers.

In providing cable grounding means, it is generally consideredundesirable Ito use a two posit-ion switch; that is, one which goe-sdirectly from the energized position to the ygrounded position. Suchswitching is considered undesirable because of the capacitive effect ofthe energized cable, and also due to the possibility otf drawing an arcfrom the energized transformer connect-ion to the grounded contact.vFrom this it will be apparent that a three position switch is presentlyneeded in the open loop feed system field to provide a cable groundingswitch for distribution transformers of loop feed systems.

It is, therefore, one object of this invention to provide a novel, threeposition, cable grounding switch.

A further object of this invention is to provide a three position switchfor loop feed systems which will enable the disconnecting of a cablefrom an energized transformer and lgrounding of such cable withoutdanger of drawing an arc from the energized transformer to the groundedcontact.

It will be understood by those skilled in this art that the lines usedto energize the various transformers of a loop feed system will carry alarge quantity of electrical power, generally, the sum of the load ofthe various transformers connected to the loop. Opening lthe contactso-f a switch carrying a lange amount of electrical power will, ofcourse, draw a substantial arc between the opening contacts. Clearly it:is desirable that -a switch to open contacts on a large quantity ofelectrical power be provided with a snap action during the opening ofthe contacts in order to break any arc which is formed during thecontact opening. Further, a snap action is desired on the closing of thecontacts of the switch to prevent pitting of such contacts and `toprevent the welding of he contacts should .they be closed on a fault.

It is, therefore, a further object of this invention to provide a novel,three position, cable grounding switch having snap action on bothopening and closing of all contacts.

Briefly, a preferred form of the .three position, cable grounding switchof this invention comprises an actuating member which is pivotallysecured to a mounting member. A pair of movable lcontacts are pivotallymounted on the mounting member and connecting means are providedconnecting the movable contacts to the actuating member. Another pair ofcontact means Vare lixedly positioned on the mounting member, one ofwhich is adapted to be connected to -a transformer, while the other isfor connection to a ground. The relation between the actuating memberand'the movable contacts is such that in one position of the actuatingmember the movable contacts are in open position. In another position ofthe actuating member one movable contact is connected to the fixedtransformer contact while the other movable contact is open. Ina thirdposition of the actuating member the other movable contact is connectedto the fixed ground con-tact while the one movable contact is opened.Spring means are provided connected between each movable contact and themounting member to provide snap action in both opening and closing withthe fixed contacts.

The invention which is sought to be protected will be clearly lpointedout `and distinctly claimed in the claims which are appended hereto.However, it is believed that the yfull scope of this invention, as wellas the manner in which its various objects and advantages are obtained,as well as other objects and advantages thereof, will be more fullyunderstood [from the following detailed description of a preferredembodiment thereof especially when considered in the light of theaccompanying draw- Y FIGURE? 2 is a side view of the switch shown ein`FIG. 1;

FIGURE 3 is a plan view similar to FIG. 1 showing the switch in anotherposition; `and FIGURE 4 is a schematic representation of an open loopfeed distribution system using switches made according to thisinvention.

Reference Will now be made to thek drawings, in which like numerals willbe used to indicate like pants throughout the `various views thereof.The drawings show a novel three position, snap acting, cable groundingswitch accordingito a preferred embodiment of this invention. Thisnovel, three position, snap action, cable grounding switch finds specialutility in an open loop feed distribution systemsuch as is shownschematically in FIG. 4.

Referring first to FIG. 4, the open loop-feed system is shown ascomprising a plurality ofdistribution transformers connected in an openloop rto a source lof electrical power, such source being designated asm As shown, the loop feed system 10 is open between the. transformer 12and transformer 14.1` The distribution transformers are shown as beingserially connected to the power source 10, three on one side of the openconnection and two on the opposite side. distribution transformers areenergized through the source 10. Should one ofthe distributiontransformers develop a fault, such that it must be removed from service,for example distribution transformer 12, then it can be seen that thedistribution transformers 14 and 16 will still be energized from source10 by means of line 22, while the distribution transformers 18 and 20will'still be energized by line 24 from the source 10. To removedistribution transformer 12 from the energized line, it is necessary todevise some disconnecting means to discon.

nect line 26=between distribution transformers 12 and 14 f (presentlyshown as being opened between these transformers) and also to disconnectline 28 betweentransformers 12 and 18. 2 To obtain this desireddisconnection it is necessary that switch means be provided in each`former 12 Vmay be used to disconnect transformer 121 from the line 26,also connecting line 26 to the grounded contact 36, as shown. Further,the switch 38 intransformer 12 may be used to disconnect transformer 121from line 28, the switch presently' being shown-as connecting line 28tothe transformer contact 40, ywhich would, of course, energizetransformer 12. However, ascan be seen, switch 38 mayk also Ybe moved toprovide connectionto the ground contact 42 in'transformer 12, thusdisconnecting transformer 12 from line 28 and grounding line28'atcontact 42. In the same, manner,

Thus all the.

4. opened-to remove energy from the line 28. whichis connected by meansYof switch 38tftotransformer 12. In opening switch 44 .itI is vdesiredthat the-switch firstbe moved to anaopen position, Itopreventadrawingany arc from the contact 46 to the: grounded contact-48,tfprior to grounding ofthe cable 28pat contact, 48. Of'fcourse,'it :v

will also be understood that with the switch '38 connected totransformercontact;40 in transformer 12, even @though a fault hasrdeveloped .intransformerl 12, due to capacitance elfectwithin the transformer, vaswell as within the.` line y28, it is desirable to 1first open switch 38prior to grounding the switch 44 at contact 48.1 .Y Thus, as will beunderstood,y with a fault developed at. transformer- 12,'`

switch 44 lwill iirst -be opened, then switch 38 will be opened fromcontact 40 andafter opening willvthen be moved to grounded-contact 42,thenaswitch 44,- ifadesired, may also be moved to grounded contact.48.However, with the end of line 28 in transformer 12 grounded i on contact42, it would not'be necessary t-o ground the;

opposite end of linea 28:1 Thus, it will be .seenthat by Withtheiydisconnection :made by gized. Transformers 14 and 16 tareenergizedby means of line 22 Iand transformers V18 :and 20 fare.energized by means of line 24. Thus the transformer-12 is effectivelyremoved frornthe electrical power and may be repaired Y or changed outas necessary without disturbingY thel Y energization of the-othertransformers in ythe system.l

Of course, fromy the above it will be apparent that if"` lit weredesirableto disconnect line 28 ;such that the line 28 might be inspectedor replaced as necessary, then line 28 may be removed from transformer-12 and=18rin the f manner previously indicated while transformer 12.maybe connected to; transformer 14 VVby meanstoffswitches 30Y and 34suchthatftransformer; 12 would then be energized from line 22 throughtransformers 16 and 14 and line'26. Transformers 18 and `20would bestill energized through line; A24 and thetcable section 28 Iwould becompletely Y disconnected from thek distribution loop feed system withaswitch 44 in transformer-18 may be used to disconnect line 28 fromtransformer' 18; presently shown asbeing connected 'to transformercontact 46.A Of course, switch in transformer 12, which is presentlyshown as being, connected through line 28 to the transformer 18,ltherebyf being energized by means of line 24 from source 10 fthroughtransformers 20 and 18 with the present position t of the variousswitches, it is desirable that switch 44 be out in any manner disturbingthe energization :of the various transformers in the loop feed system.The novel three position, snapaction, cable grounding switch of 'thisinvention is uniquely designed for useV in the above type system.However,.as will be apparent fromthe fol-a` lowing description, thethree position, snap acting, cable grounding switch ofthis invention isnot necessarily lim-t ited to .use in loopfeed systems. .t

acting,cablel grounding .switch comprises an vractuating member suchasthe lcranlct) whichis pivotally secured to a mounting member 52, asshown in FIGS. l :and 2J The mountingA membery 52"*may-y be atransformer wall Yor and 56 are `provided being `pivotally mounted`toyan `insulating member 58, which may lbe connected to the tankl wall52 in any desired manner,i such as for example" by the insulatingbushings 60, 62.5 Movable contacts 54 and 56 are movable into and out ofengagement with ithe. fixed contacts 64, 66,:respectively'f. Spring:means 68, 70

are provided'connected betweenV contact 54-and insulating member58,-whilespring means72',74" 'are provided connected between :contact 56and mounting member S8 to aid in movinggthe contacts into and out ofengagement Referring nowto FIGS; 1 and 2 of the drawing, a pre-` ferredembodiment of the novel, three position snap ac.-l tion` cablegroundingswitch ofthis invention Willbe de-; scribed in detail..Y Asshown,'the rthre.e position, snap4 with the fixed contacts 64 and 66, inthe manner to be hereinafter more fully described. Connecting means 76and 78 are provided, connected between movable contacts 54 and 56,respectively, and the actuating member 50 for moving the movablecontacts into and out of engagement with the fixed contacts 64 and 66.

As shown in the preferred embodiment of FIGS. 1 and 2, the cablegrounding switch of this invention is in its open position whereby themovable contacts 5'4 and S6 are out of engagement with both fixedcontacts 64 and 66. In this position, actuating member 5G is in the openposition with connecting means 76 and 78 in a substantially verticalposition. The actuating member 50 is pivotally connected to the mountingmember, such as tank wall 52,

'by means of a shaft 80 which extends through the tank wall to anactuating handle 82. As will be understood, the three Iposition, snapacting, cable grounding switch may be installed Within a distributiontransformer while the actuating handle 82 is on the exterior of suchtransformer to allow its ready manipulation either by a switch stick ofby hand, as desired. An indicator may also be provided with operatinghandle 82 to indicate the position of the cable grounding switch.

The actuating member 50 is pinned to the shaft member 80 by means of pin84 as indicated in FIG. 2 while the actuating handle 82 is connected tothe other end of the shaft 80 by means of pin 86. The shaft 80 extendsthrough the tank wall by means of la sealed bearing 88, in a mannerwhich is well understood by those skilled in this art.

Handle 82 is provided with a stop means in the form of a pin member 90which extends through a bushing 92 and is held in the position shown bymeans of a spring, indicated lby the d-otted member 94. As will beunderstood, the spring 94 holds pin 90 in its extended position as shownin FIG. 2. In this position, the extended pin 90 contacts the stop 96,which is mounted on tank wall 52, as shown. In order to move the handlebeyond stop 6 it is necessary to grasp the knurled knob 9S connected topin 90 and compress spring 94 to move the extended portion of pin 90 outof engagement with stop member 96. The handle 82 may then be moved in aposition lbeyond stop 96. As will be understood, it is desirable toprovide this type of stop means such that in moving the switch from oneposition where one of its contacts is closed to the opposite positionwhere another of ts contacts is closed, that the handle positively stopin the open position demonstrated in FIG. 1 of the drawing. This is toprevent the accidental movement of the cable grounding switch from theenergized cable position to the cable grounding position.

The movable contacts 54 and 56 are shown in the form of a pair of blademembers which are pivotally mounted to the insulating member 58 bybearing means 100 and 102, respectively (best shown in FIGS. 2 and 3).As above mentioned, the insulating member 58 may be mounted to the tankwall 52 by means of bushings 60, 62. The insulating member 58 is securedto the bushing by screw means 104, 106 which only extend partially intothe bushing, as indicated by the dotted line in FIG. 2. Of course, theopposite end of the bushing may be similarly secured to the tank wall52, such Ias for example, by screws indicated at 108 in FIG. 2. Aplurality of terminals indi-cated at 110, 112 and 114 are provided onthe insulated member 58-in the manner shown. As will be understood,especially as indicated in FIG. 4 of the drawing, the central contact110 of the cable grounding switch is adapted to be connected to a cablemember such as cable 26 or 28 shown in FIG. 4. The terminal 112 isadapted for connection to the high voltage le-ad of a distributiontransformer, while the contact 114 is adapted to be connected to agrounded portion of the transformer such as is indicated byswitch 38 inFIG. 4.

As is apparent from FIGS. 1 and 2 of the drawing, the movable contacts-54 and 56 are electrically connected to terminal through the strap 116and the Ibearings 100, 102. The cable connected to terminal 110 may beconnected to terminal 112 by means of movable contact 54 when themovable contact 54 engages the fixed contact 64. In a similar manner,the cable connected to terminal 110 may be also connected to terminal114 when movable contact 56 engages fixed contact 66. Thus, in thismanner, the terminal 110 and any cable connected thereto may beconnected to either of the tWo terminals 112, 114, alternately, by meansof the movable contacts 54 :and 56.

As can be seen particularly from FIG. 2 of the drawing, the movablecontacts 54 and 56 are in the form of a pair of blade members providedwith biasing spring means, as indicated at 118, 120, which serve totighten the electrical connection between the switch blades and thestationary contacts. Spring members 118 and 120 are in the form 4ofcompression springs which surround the pin or bolt 122 which extendsthrough the switch blades in the manner particularly shown in FIG. 2. Ascan Ialso be seen the bolt 122 also connects the switch blade to theconnecting means 76. As will be understood las the switch blades closeon the fixed Contact the lblades are forced against the contact toprovide a good electrical connection. Further, the biasing springs 118,120 force the switch bades into iirm friction contact with the fixedcontacts thereby requiring a certain force to overcome the friction andopening the movable contacts. As can be seen the spring means 68 and 70for movable contact 54 are connected to the pin or bolt 122 at one end,while the opposite end is Iconnected to -a fixed member 124 which isbolted to the strap 116 and the insulating member 58. As will beapparent, especially from FIG. 1 of the drawing, the tension springs 68and 70 connected to fixed contact 54 Iand tension springs 72, 74connected to movable contact S6, are over or above the pivotal contactpoint 100 and 102, respectively, thereby providing an over-center meansto aid in holding the movable contacts in their open position, shown inFIGS. 1 and 2. Of course, it will be evident that in closing either ofthe contacts the overcenter action of these springs 68, 70 or 72, 74must be overcome in the contact closing operation.

The connecting means 76, 78 which connect the actuating member 50 tomovable contacts 54 and 56, respectively, will now Ibe described. As canbe seen from FIGS. 1 and 2, the connecting means are in the form of apair of rods, such as rods 126 and 128 of the connecting means 76. Therod 126 is connected between movable contact 54 and rod 128 and is inthe form of an insulating rod, while the other member 128 may be eitheran insulating or -a metallic channel member. As shown, the insulatingrod 126 is connected to the movable contact 54 by means of the pin orbolt 122 and is connected to channel member 128 by means of bolts 130.The member 128 is in the form of a channel in which is mounted a springmember 132. The spring member 132 is connected between the bolt and abearing member 134. The bearing member 134 connects the connecting means76 to one portion of hte actuating member 50 as sho-Wn. The channel 128is provided with la slotted opening 136 through which the bearing 134extends and in which it is movable during operation of the actuatingmeans 50. In the open position shown in FIG. 1, both of the springs,such as 132 in channel 128, are in their relaxed position with the movable contacts in the upward and open position, as shown.

Referring now .to IFIG. 3 of the drawing, when the actuating member 50is rotated in a clockwise direction, to connect movable contact `54 withfixed contact 64, it will be apparent that the spring member 132 inchannel `128 of connecting means 76 is placed in compression, pushingagainst the pin 130 connecting 128 and 126. As will be apparent thespring y132 will store energy in compression until such time as theforce applied to contact 54 is sufficient to overcome the tension orforce of the springs 68 and 70. At this point, the contact 54 will beginto close on contact 64 with the snap action of the stored energy in thespring 132. At the same time, as springs 68 and 70 begin tomovedownwardly with the movable contact 54 they will reach theover-center position with reference to the bearing 160 and will then addtheir energy to that of the compression spring 132, iirmly closingcontact 54 on contact 64 with a snap action.

Referring toboth FIGS. l and 3, it rwill be apparent that when theactuating member 50y is rotated in a counterclockwise direction to opencontacts 54 and 64 that the spring member 132 will be placed in tension,being stretched within channel 1.28 between the pin 130 and the bearing134. The stretching of the spring 132 willy store,

energy which is suddenly -released when the stored energy of the spring132 overcomes the' friction between movable c-ontact 54 and lfixedcontact 64 and thel over-center forceofthe springs 68 and 70. At thispoint, the movable contact 54 Will open from the fixed contact 64 with asnap.

action. Of course, itwill be understood that as the mova'ble contact 54begins Yto move upwardly, the tension springs 68 and 70 will move pastthe over-center positiony With reference to the bearing 100 and willthen aid in moving the movable contact '54 to the open position shown inFIG. 1. From the above it will'be apparent that by means of the spring132 and the tension springs 68 and 70 that the movable contact 54 ismoved with -a snapJ action in both opening and closing of the con-tactwithout regard for thel speed of movement of .the lactuating handle 50.'Of course, -it will be apparent that the same action is obtained in theopening and closing of the movable contacts 56 with the fixed contact66.

As shown, particularly in FIG. 2, pin members .140y

and 142 are provided on the insulating rod 126 and the insulating rod inthe c-onnecting means 78 to prevent movable contacts 54 and 56 frombeing opened too far Y during the opening sequence. This will preventthe springs68 and 70 or springs 712 and 74 from pulling the movablecontacts 54 and 56 too far in the open position, which might preventtheir being properly closed on actuation of the handle 82. In a similarmanner, stop means may be provided in the closing position of contacts54 i and 56 by means of 'Washers 1144, 146 which are mounted on thebolts l1'48, 1150 which are used to attach t-he fixed contact'64 andterminal 112 and fixed contact 66.and terminal 114, respectively, to the`insulated memberySS. These washers 144, 146 will contact thesides ofthe blades in contacts 54, 56, in the manner especially shown in FIG.`3, to prevent the springs 68, 70, and 72, 74 from moving contacts 54and 56, respectively, too far in the closed position.

From the above detailed description of a preferred embodiment of thisinvention it will be apparent to those Skilled in the artthat there hasbeen shown and described a novel, three position, snapy acting, cablegroundingV switch which may be particularly useful in open loop feeddistribution systems. `It will also be apparent that this threeposition, snap acting, cable grounding switch may also be used in othertypes of systems where it is desired to provide a switching means Wherecontacts may be yprovided lwhich are opened orV where one contact isclosed either on an energized member or a grounded contact. While thepreferred embodiment of the .invention has been described inV accordancewith the patent statutes ,it

will be understood that many modications may be made in the constructionand materials of this described switch without departing from the spiritand scope of the kinvention set forth. Such modifications are consideredincluded, insofar as they fall within the scope of the invention denedin theclaims appended hereto.

What is claimed as new and which it is desired to ysecure by LetterslPatent of the United States is:

.1.; A three position, snap acting, cable vgrounding switch comprising:an actuating membermeans'for piv-V otally securing said actuating memberto a mounting means, an insulating member, means for xedly positioningsaid insulating member to the mounting means, a pair of fixed contactsmounted n said insulating memtactsfor electrical connection to anelectrical cable,.conV necting means connecting said movable contactsito said actua-tingrmember for movement of said movable contactsy into.and out of engagementwith said fixed contacts,

in one position of saidactuating member one yof said movable contactsengaging .one of said xed contacts to electrically connect saidthirdterminal to said first ter-1, minal, in a second position of saidactuating member said movable contacts being disengaged `from saidxedcontacts,in'a third position of said actuating member the other ofsaid movable contacts engaging the other of said dixed contacts toelectrically connectV said third terminal 1 to said second terminal, anda plurality of separate spring means individually connected between eachof said moyable contacts and said insulating member in over-centerrelation to aid in opening and closing ;each of said contacts with asnapiaction.

as claimed ,inV claimt 1 in which an operatingy handle `is providedconnected tosaid pivotally securing means for actuating said actuatingmember, stop means on said hany dle to positively stop said actuatingmember inzsaid second position when moving between said ifirst andsaid'` third position, said stop; means being `releasable afterlstopping of said handle to allow .further movement of..

said actuating member.

3. fAcable .grounding ,switch for vuse inea distribution open loop Vfeed`system in whicheach distribution transformer of the'system 'isipr-ovidedwith a pair of cable grounding switches, said cable. groundingswitch "comprising an actuating member adaptedto be secured to atransformer, `an insulating member forming part of said switch andfadaptedto be secured toa transformer, a;pair ofk fixed contactssecuredto saidinsulating member, one of vsaid kfixed contacts ladapted forconnection to the high.

voltage lead of a transformer, the other of such xed contacts adaptedforiconnection to a ground in a transformer, a pair of movablecontactspivotally mounted on said insulating` member, a terminal meanselectrically connected to said movable contacts and yadapted forconnectiony to a cable for energizinga transformer, connect.-A

ing means connecting said movable: contacts` to said ac- `tuating memberfor movement ofsaid movable: contacts into and Outbfengagement with saidfixed contact, said actuating .member being operable to placeeitherofsaid movable contacts in engagement with one of said txed contacts andbeing movable to a thirdtposition where .both movable contactsaredisengaged from said fixed contacts, spring meansV in said connectingmeans, a plurality of separate: spring; means individually connectedbe-y tween each of said movable `contacts and .said insulating member inover-center relation, said spring means inV said connecting means andsaid plurality of separate spring means cooperating to move .saidrmovable contacts into and out of engagement with said Vfixed contactswith la snap action` References Cited by the Examiner` UNITED STATESPATENTS 1,482,051 1/ 1920 Turner 200--42Y 2,874,338 2/1959 Pease 200.68X 3,015,005 12/1961 2 Albert 200-@67 ROBERT K.V SCHAEFER, PrimaryExaminer;`

ROBERT S. MACON,Examner.

1 H; E HOHAUSER,I Assistanty Examiner.`

2. i A three position snap acting cable grounding switch

1. A THREE POSITION, SNAP ACTING, CABLE GROUNDING SWITCH COMPRISING: ANACTUATING MEMBER, MEANS FOR PIVOTALLY SECURING SAID ACTUATING MEMBER TOA MOUNTING MEANS, AN INSULATING MEMBER, MEANS FOR FIXEDLY POSITIONINGSAID INSULATING MEMBER TO THE MOUNTING MEANS, A PAIR OF FIXED CONTACTSMOUNTED ON SAID INSULATING MEMBER, A PAIR OF MOVABLE CONTACTS PIVOTALLYSECURED TO SAID INSULATING MEMBER, A FIRST TERMINAL MEANS ELECTRICALLYCONNECTED TO ONE OF SAID FIXED CONTACTS FOR ELECTRICAL CONNECTION TO ANELECTRICAL APPARATUS, A SECOND TERMINAL MEANS ELECTRICALLY CONNECTED TOTHE OTHER OF SAID FIXED CONTACTS FOR ELECTRICAL CONNECTION TO A GROUND,A THIRD TERMINAL MEANS ELECTRICALLY CONNECTED TO SAID MOVABLE CONTACTSFOR ELECTRICAL CONNECTION TO AN ELECTRICAL CABLE, CONNECTING MEANSCONNECTING SAID MOVABLE CONTACTS TO SAID ACTUATING MEMBER FOR MOVEMENTOF SAID MOVABLE CONTACTS INTO AND OUT OF ENGAGEMENT WITH SAID FIXEDCONTACTS, IN ONE POSITION OF SAID ACTUATING MEMBER ONE OF SAID MOVABLECONTACTS ENGAGING ONE OF SAID FIXED CONTACTS TO ELECTRICALLY CONNECTSAID THIRD TERMINAL TO SAID FIRST TERMINAL, IN A SECOND POSITION OF SAIDACTUATING MEMBER SAID MOVABLE CONTACTS BEING DISENGAGED FROM SAID FIXEDCONTACTS, IN A THIRD POSITION OF SAID ACTUATING MEMBER THE OTHER OF SAIDMOVABLE CONTACTS ENGAGING THE OTHER OF SAID FIXED CONTACTS TOELECTRICALLY CONNECT SAID THIRD TERMINAL TO SAID SECOND TERMINAL, AND APLURALITY OF SEPARATE SPRING MEANS INDIVIDUALLY CONNECTED BETWEEN EACHOF SAID MOVABLE CONTACTS AND SAID INSULATING MEMBER IN OVER-CENTERRELATION TO AID IN OPENING AND CLOSING EACH OF SAID CONTACTS WITH A SNAPACTION.